BRIGHT METAL-POOR STARS FROM THE HAMBURG/ESO SURVEY. II. A CHEMODYNAMICAL ANALYSIS
Name
Beers-2017-RIGHT METAL-POOR STARS FROM THE HAM.pdf
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1.53 MB
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Adobe PDF
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Author(s)
Beers, Timothy C.
Placco, Vinicius M.
Carollo, Daniela
Rossi, Silvia
Lee, Young Sun
Norris, John E.
Dietz, Sarah
Masseron, Thomas
Frebel, Anna L.
Date Issued
November 2016
Journal
The Astrophysical Journal
Publisher
IOP Publishing
Citation
Beers, Timothy C. et al. “BRIGHT METAL-POOR STARS FROM THE HAMBURG/ESO SURVEY. II. A CHEMODYNAMICAL ANALYSIS.” The Astrophysical Journal 835.1 (2017): 81. © 2017 The American Astronomical Societ
Version
Final published version
Abstract
We obtain estimates of stellar atmospheric parameters for a previously published sample of 1777 relatively bright (9 < B <14) metal-poor candidates from the Hamburg/ESO Survey. The original Frebel et al. analysis of these stars was able to derive estimates of [Fe/H] and [C/Fe] only for a subset of the sample, due to limitations in the methodology then available. A new spectroscopic analysis pipeline has been used to obtain estimates of T[subscript eff], log, g, [Fe/H], and [C/Fe] for almost the entire data set. This sample is very local—about 90% of the stars are located within 0.5 kpc of the Sun. We consider the chemodynamical properties of these stars in concert with a similarly local sample of stars from a recent analysis of the Bidelman and MacConnell "weak metal" candidates by Beers et al. We use this combined sample to identify possible members of the halo stream of stars suggested by Helmi et al. and Chiba & Beers, as well as stars that may be associated with stripped debris from the putative parent dwarf of the globular cluster Omega Centauri, suggested to exist by previous authors. We identify a clear increase in the cumulative frequency of carbon-enhanced metal-poor (CEMP) stars with declining metallicity, as well as an increase in the fraction of CEMP stars with distance from the Galactic plane, consistent with previous results. We also identify a relatively large number of CEMP stars with kinematics consistent with the metal-weak thick-disk population, with possible implications for its origin.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.3847/1538-4357/835/1/81
